It heightens comparisons.
No one seriously interested in women can have failed to notice the disproportionate frequency with which a gorgeous one will be seen with, well, a real dog.
This is no accident.
The dog wants to be seen with beauty, hoping some rubs off, while the stunner heightens her appeal by comparison when hanging out with the woofer.
Case in point:
G1, kit lens.
This gorgeous young woman had some sort of crick in her knee – or not – and was making quite a production of it. Her three dowdy friends were knocking her performance, but they were not her audience. I was.
Most enjoyable. And the lovely light, right into the lens, only heightens the impression.